Fiber optic connectors have been utilized in the past to axially align an optical fiber with an active device such as a light emitter or light detector, in which either light is emitted from a central region of the face of the active device or light is detected at the central region. Prior art connectors for such a purpose have been termed "active receptacles" which are devices which house an active opto-electronic device, either an emitter or detector, and provide a means to connect an optical fiber to the device with an efficient transfer of light between the two. Despite the high demand for such a device, devices currently available have been inefficient or costly, mainly because of the tight tolerances necessary to couple light efficiently into an optical fiber that is only a few thousandths of an inch in diameter.
There presently exists a class of active devices which emit light, in which the output from a light emitting diode (LED) is focused to a spot at the face of the diode package. While the die producing the light output may be accurately positioned with respect to its substrate, the package, usually including a can or shell, has great variation in its outside diameter such that alignment of an optical fiber with respect to the focused spot is difficult when utilizing the outside dimension of the can or shell for fiber positioning purposes. Under ordinary circumstances, were the can or shell to be uniform in outside dimension, all that would be necessary for the active receptacle would be to provide a connector with a recess into which the active device is either press-fit or retained in a sliding fit. The optical fiber could, under such circumstances, be accurately coaxially positioned with respect to the active device through the utilization of a conventional ferrule which would be inserted into a central alignment channel communicating with the recess. However, since the cans or shells utilized to house active devices are variable in size, some other means of coaxially locating a fiber with respect to the center line of the active device is required.
By way of further background, optimal positioning of an optical fiber vis-a-vis a predetermined point on an active device has been accomplished either by the pigtailing of the fiber to the actual device or adjusting the position of the active device within the housing so as to maximize light transfer between the fiber and the active device. Optimal positioning of the light emitting diode in a connecting housing refers to adjusting the position of the light emitting diode in an oversized housing until the output from the fiber is maximum. Pigtailing refers to a practice in which the fiber is micropositioned to the emitting die of the particular light emitting diode used. Both of these approaches involve excessive labor and are time consuming.